1. Technical Field
The following descriptions relate to an image scanning device having a reading unit, which extends in a main scanning direction and is movable in an auxiliary scanning direction, configured to move to scan an original sheet placed on a transparent plate.
2. Prior Art
An image scanner configured to scan original sheets which is being fed by a sheet feeder has been known as well as an image scanner configured to scan an original which is placed on a predetermined scanning position. The former is known as a scanner using an ADF (automatic document feeder), while the latter is known as an FBS (flat bed scanner).
The FBS is generally provided with a transparent glass plate on which an original sheet is placed and an openable/closable sheet holding cover that covers and holds the original sheet placed on the glass plate. Below the glass plate, an image scanner such as a CIS (contact image sensor) is provided. The CIS has multiple CMOS elements, optical elements including lenses, and light source such as a plurality of RGB LEDs (light emitting diodes). The multiple CMOS elements are arranged in line and light emitted by the light source and reflected by a surface of the original sheet bearing an image, and generates an electrical signal corresponding to the intensity of the received light.
The ADF is typically provided on the sheet holding cover and feeds the original sheets stacked on a sheet feed tray, which is also provided on the sheet holding cover, one by one into a sheet feed path. Typically, another (second) transparent glass plate is arranged next to one end of the transparent glass plate on which the original sheet is placed. The original sheet fed by the ADF passes over the second transparent glass plate. Below the second transparent glass plate, a scanning unit is located and scan the image on the original sheet that is fed by the ADF and passing through the second transparent glass plate. The original sheet passed over the second transparent glass plate (and image there on has been scanned), the original sheet is directed to an ejection tray by way of a scoop-up guiding member arranged next to the second transparent glass plate.